“I’ve had very productive conversations with EPA over the last several weeks, and believe the agency has taken significant steps forward on our five transparency requests,” Vitter said in a statement Tuesday.

“These are huge, significant steps forward to bringing transparency to the agency, and I see no further reason to block Gina McCarthy’s nomination, and I’ll support moving to an up-or-down vote on her nomination,” he added.

McCarthy is currently the EPA’s top air pollution regulator. Vitter’s action brings the Senate a step closer to a vote on the nomination, which the White House first sent to the Senate four months ago.

He said EPA, the Interior Department and the U.S. Army Corps of Engineers have failed to demonstrate that they have ended bureaucratic infighting over the St. Johns Bayou-New Madrid Floodway Project.

Blunt, in a statement, said “I look forward to hearing conclusively whether the Corps, EPA, and [Interior’s Fish and Wildlife Service] have reached an agreement on all of the facts surrounding this project.”

Vitter and several other Republicans, meanwhile, have blocked McCarthy as leverage in their quest for more “transparency” from the EPA.

Vitter’s office said Tuesday that the EPA made several commitments.

They include mandatory retraining of more than 17,000 workers on public records law, and publishing online, upon receipt, outside groups' petitions for rulemaking and notices of intent to sue.

Republicans have been attacking what they contend is an un-transparent “sue and settle” technique of policymaking.

He also claimed victories on the EPA’s use of data.

“EPA has initiated the process of obtaining the requested scientific information, as well as reaching out to relevant institutions for information on how to de-identify and code personally identifying information that may be in any of the data. For the first time we should be able to determine if there is any way of independently re-analyzing the science and benefits claims for a suite of major air regulations,” Vitter’s office said in a summary of what it called new commitments from the EPA.